Flotation material and process of making same



Patented Dec. 23, 1930 UNITED STATES PATENT OFFICE STUART MILLER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE BARRETT COMPANY, A CORPORATION OF NEW JERSEY FLOTATION MATERIAL AND PROCESS OF MAKING SAME No Drawing.

not new. I have discovered a material consisting of alpha-naphthylamine, together with certain other related compounds which may be used to great advantage in flotation. The alpha-naphthylamine, which has up to this time been used for flotation work, has been known commercially as X-cake. It is substantially crude alpha-naphthylamine, having a solidification point of approximately 38 to 40 0., and containing 85 to 92% of material analyzing as alpha-na'phthylamine by the nitrite titration method of analysis. This producthas been made by'the nitration of naphthalene to alpha-mono-nitro-naphthalene, and the reduction of this compound to crude alpha-naphthylamine by the use of iron and hydrochloric acid. This crude material has been separated from the residual iron-oxide and excess iron, resulting from the reduction, by distillation or by extraction with a volatile solvent, such as coal tar solvent naphtha, for example, followed by removal of the solvent from the alphanaphthylamine by distillation. The product has been expensivethus making it costly to use it as a flotation agent.

The user of the X-cake has found it desirable to mix with it approximately 40% by weight of crude xylidine. The xylidine itself probably possesses some value as a flotation reagent. The main reason for its use is,-

however, to lower the solidification point of the alpha-naphthylamine to such an extent that the mixture may be maintained as a liquid to facilitate handling.

The mixture ofal-pha-naphthylamine and crude xylidine has been known commercially as X. Y.-mixture and has been more expensive than the X-cake. The increase over the cost of X-cake is due to the use of the more expensive xylidine. The cost of the a shortage of Xylidine has at times precluded the use of the X. Y.-mixture.

Application filed November 17, 1924. Serial No. 750,505. I

The product which I have found to use as a flotation reagent is made as follows: Crude alpha-naphthylamine is manufactured exactly as in the case mentioned above. It is recovered from the iron-oxide and iron by extraction with a volatile solvent. The solution of crude alpha-naphthylamine is then evaported for removal of the solvent. The evaporation is continued until only about 10% by volume of solvent remains in the crude alpha-naphthyl'amine. The crude'is then caused to partially crystallize by cooling to approximately 25 C. The crystal mass is crushed and the mother liquor is removed by use of a hydraulic press or a centrifuge. The mother liquor is evaporated for recovery of the volatile solvent. This evaporated mother liquor I shall term mother liquor 25:1. This mother liquor, substantially freed from volatile. solvent, may be cooled and a further recovery of alpha-naphthylamine crystals may be made. The mother liquor resulting from this second crystallization I shall term mother liquor #2. The crystals obtained in each case are then converted into refined alpha-naphthylamine bv' the usual method. It may, under certain conditions, be desirable to use a solvent other than solvent naphtha. Such organic materials or solvents as aniline, toluidine, xylidine or similar; solvents may be employed.

The mother liquor, either #1 or #2, is the material I have discovered to be of value as a flotation reagent. Mother liquor #1 contains from 50 to 60% material analyzing as alpha-phthylamine by the nitrite nitration method. Mother li nor #2 ordinarily contains 35 to 50% 0 material analyzing as alpha-naphthylamine, but if the cooling of mother liquor #1, in the further recovery of alpha-naphthylamine, has been carried out at low temperatures, such as are obtained by the use of refrigeration, then mother liquor #2 may contain as little as l5 to 20% of material analyzing as alpha-naphthylamine.

The mother liquors possess distinct advantages as flotation reagents. The cost is considerably lower than in the caseof X-cake. This is due partly to the factthat the material has been recovered coincident with the recovery of alpha-'napht-hylamine for the production of refined alpha-naphthylamine. It isdue principally to the fact that the mother liquor #1 or #2 consists largely of products which are entirely destroyed in the ordinary recovery of valpha-naphthyla'mine as refined 'naphthylamine. The -materials are, therefore, by-products which have in the past not, been available. Approximately 0.2 to 0.3 of a pound of mother liquor per pound of refined alpha-naphthylamine will be produced. A further distinct advantage is that these materials require far less Xylidine than does QC-cake to maintain them in the liquid.

. the use of xylidine is not desired, small quantities of the volatile solvents used for the recovery of crude naphthylamine from the ironoxide, may be used for lowering the solidifi-. I cation point of the mother liquor.

The mother liquors alone or-mixed with Xylidline, are employed in the manner commonly used for the recovery of ores by X; Y.-mixture. 7 When a flotation test was made with a high quality standard flotation reagent of the sort that has been used for several years, known in thetrade as Barrett No. 4, using a sample of ore that assayed 1.28% of copper, it was found that 72.8% of the copper was extracted. It should be pointedout that Barrett No. 4 oil is a coal tar oil distilling roughly between 200 and 300 C. and containing about 25% of tar acid. In the test 2000 parts by weight of ore were treated with 1 part by weight of the No. 4 oil.

When the test was made using a sample of the'same orewith the mother liquor above described as the flotation reagent, 73.2% of the copper was extracted, thus showing that the mother liquor as a flotation reagent extracts a larger percentage of copper than the high grade flotation reagent heretofore used. Two thousand parts by weight of the ore were treated with 1 part by weight of the mother liquor. Y

I claim:' I 1. A flotation reagent comprising a solvent and the mother liquor obtained in the purification of crude alpha-naphthylamine by forming a solution of crude alpha-naphthylamine in a solvent, partially crystallizlng the alpha-napthylamine of the solution, and separating the crystals.

2. AL flotation agent comprising. amino compounds and the mother liquor obtained in the purification of crude a-lpha-naphthylamine by forming a solution of crude alphanaphthylamine in a solvent, partially crystallizing the alpha-naphthylamine of the soluof a liquid flotation reagent, comprising the tion, and separating toe crystals.

3. A flotation agent comprising xylidine and the mother liquor obtained in the purification. of crude lalpha-naphthylamine by forming a solution of crude alpha-na hthylamine in asolvent, partially crystallizing the alpha-naphthylamine of the solution, and separating the crystals.

4. A flotation agent comprising 10% to 20% Xylidine and the mother liquor obtained in the purification of crude alphanaphthylamineby forming a solution of crude alpha-naphthylamine in a solvent, partially crystallizing the alpha naphthylamine of the solution, and separating the crystals.

5. The process of producing a liquid flotation reagent which comprises dissolving crude alpha-naphthylamine in a solvent,

evaporating off the major portion of the solvent, partially crystallizing the naphthylamine content of the solution and separating the mother liquor from the crystals.

6. The process of producing. a liquid flotation reagent which comprises dissolving crude alpha-naphthylamine in a solvent, evaporating off the major portion of the solvent, partially crystallizing the naphthylamine content of the solution, separating the mother liquor from the crystals and adding an amino compound to said mother liquor.

7. The process of producing a liquid flotar' tion reagent which comprises dissolving crude alpha-naphthylamine in a solvent,

evaporating off the major portion of the solvent, partially crystallizing the naphthylamine content of the solution, separating the mother liquor from the crystals and adding xylidine to said mother liquor.

' 8. The process of producing a liquid flotation reagent which comprises dissolving crude alpha-naphthylamine in a solvent, evaporating oil the major portion of the solvent, partially crystallizing the naphthylamine content of the solution, separating the mother liquor from the crystals, evaporating'the mother liquor for further recovery of the solvent and adding an amino compound to saidmother liquor. 9. A flotation reagentcomprising a solution of alpha-naphthylamine in the mother in a solvent, partially crystallizing the alphanaphthylamine of the solution, and separating the crystals.

11. A solvent for use in the production mother liquor obtained by the purification of crude alpha-naphthylamine by forming a solution of crude alpha-naphtnylamine in a solvent, partially crystallizing the alphanaphthylamine of the solution, and separating the crystals.

12. A solvent for use in the production of a liquid flotation reagent from crude alpha-naphthylamine, comprising a mixture of xylidine and the mother liquor obtained by the purification of crude alpha-naphthylamine by forming a solution of crude alphanaphthylamine in a'solvent, partially crystallizing the alpha-naphthylamine of the solucontent of the solution and tion, and separating the crystals.

13. A flotation agent comprising the mother liquor obtained in the purification of crude alpha-naphthylamine by. forming a solution of crude alpha-naphthylamine in a solvent, partially crystallizing the alphanaphthylamine content of the solution, and separating the crystals.

14. In a process for concentrating ores by flotation, the improvement which consists in employing as a flotation agent a mother liquor comprising alpha-naphthylamine and other constituents of crude alpha-naphthylamine, obtained by forming a solution ofcrude alpha-naphthylamine, partially crystallizing the alpha-naphthylamine content of the solution, and separating the crystals.

15. In a process for concentrating ores by flotation, the improvement which consists in employing as a flotation agent a mother liquor comprising alpha-naphthylamine and other constituents of crude alpha-naphthylamine, obtained by forming a solution of crude alpha-naphthylamine in an organic solvent, partially crystallizing the alphanaphthylamine content of the. solution and separating the crystals.

16. In a process for concentrating ores by flotation, the improvement which consists in employing as a flotation agent a mother liquor comprising alpha-naphthylamine and other constituents of crude alpha-naphthyl-- amine, obtained byforum a solution of crude alphax-naphthylamine 11 solvent naph- 

